Muscles of hand
Musculi manus
Definition
The muscles of the hand are categorized into two main groups: intrinsic and extrinsic. Intrinsic muscles originate and insert within the hand itself, allowing for fine motor control and intricate finger movements. In contrast, extrinsic muscles originate in the forearm and extend into the hand via long tendons, providing powerful, gross movements.
Intrinsic muscles of the hand
The intrinsic muscles are further subdivided and include the thenar and hypothenar muscles, the lumbricals, the palmar and dorsal interossei, and others like the adductor pollicis and palmaris brevis.
Thenar muscles | Abductor pollicis brevis, Opponens pollicis, Flexor pollicis brevis | ||
Hypothenar muscles | Abductor digiti minimi, Opponens digiti minimi, Flexor digiti minimi of hand | ||
Lumbricals | |||
Interossei | |||
Other intrinsic muscles | |||
Extrinsic muscles of the hand
The extrinsic muscles originate in the forearm, with flexors positioned on the anterior (front) aspect and extensors on the posterior (back). Their long tendons extend into the hand, facilitating powerful movements of both the hand and wrist.
Flexor muscles (anterior forearm) | Examples include flexor digitorum superficialis, flexor digitorum profundus, flexor pollicis longus. | ||
Extensor muscles (posterior forearm) | Extensor digitorum, extensor digiti minimi, extensor indicis, abductor pollicis longus, extensor pollicis longus, extensor pollicis brevis. | ||
The coordinated action of both extrinsic and intrinsic muscles enables the complex and precise movements characteristic of the human hand.
References
Okwumabua E, Sinkler MA, Bordoni B. Anatomy, Shoulder and Upper Limb, Hand Muscles. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537229/
